Tire air pressure gauge



Sept. 7, `1943. l. D. FENwlcK l TIRE AIR PRESSURE GAUGE Filed Aug. 21, 1942 .FZ-:G

` Patented Sept. 7, 1943 imi. Fenwick, cannes. Y;

rsldesinafgaifgecvvhichr-,maybe secured to a tire yallve ln'lieuy 'ofthe conventionalvalve cap enable `:the 'exact instant.. reading of.:the aniountof air pressure; bresentin fa tire, thus dispensingwitnthe usual` 'nractieegorremoving e `,tlilejalvecap and applying Aa tire gauge to the ix .Anotherjfeature .0f tlieziuventibn isV t provide i a .eaauge Whichis 'screwedinto scalini-r` `er1- gement with` the threaded stem off a Vtirehvalve y .,wthout, alteration .thereof` to, avoid leakage. .of a1 from.; a. tire vand `which prevents accidental Q f airI from 4artire sl1o,u,ldl Atlieyvalve spring become .weak 0rV out Oadiustment. lfurbheneature of the. invention. ,i-s. ,theme- .vis/.19.1.1 enf. a tire eaueemhich is relativelvsmall :ill SiZQ. and. light. in Weighted .te bek attached t9.; atreyalve, and `remaiil thereon. While .the "re isdrvotatingmand not interfere with the balancefof the tire.,,

.e .further .fftiirefefftb 'invention is ,to furor i iid-e tire; aepresure'eage aiureseid, which 'S Pls eed inexpensive@ construction, easy h and' renovafrem ur Avalve and '-lssiion autunnale rentestanden@ {fo-rde to which the'gaug'e is subjection anautomobile wheel illustrating the tire gauge in position upon the tire valve.

Figure 2 lis an enlarged vertical sectional view [on the line 2-2 of Figure 1. l Figure 3 is a horizontal sectional view on the line 3-3 of Figure 2.

Referring to the drawing by reference characters, the numeral I0 designates my improved tire air pressure gauge in its entirety. The gauge II) includes a cylindrical housing I I which Acomprises anannular side Wall I2 `and an end Wall I3. The end Wall I3 is provided with an annular depression I4 which forms an annular pe- `ripheral shoulder I5. The end Wall I3'is provided with a central air inlet opening and coaxial `with the opening is an interiorly screw threaded nipple I6, said nipple being integral with the end Wall I3. Seated in the depression I4 is a metal disk I'I which is complementary to TW "fin-mili?. I theoutar n wtirigf pointerylQ reiationwiii et k 24. k'rhe mueanng pointer 2Bmoves about the dial disk 25 and cooperatesvvith the air pressure indicia or graduatons to indicate an air 4pressure reading of the gauge.

Secured axially of the diaphragm 2l and freely extending into the cylindrical shell member 28 is a stud 30, the exterior of which is provided with a spiral groove 3| into which a pin 32 extends, the said pin being i'lxedly carried by the shell member 28. A coiled expansionspring 33 encircles the shell member and has its ends respectively abut-` ting the` confronting sides of the dial disk 24 and the diaphragm 2l.

threaded stem A of a tire Yvalve B, the latter being shown in Figure las extending from the rim Cof i an automobile Wheel D. The conventional cap is removed from the stem A and the gauge IIJ is substituted therefor. 'I'he threaded nipple I B In practice, the gauge I0 is applied to the` engages the threads of the stem A and for sealing the joint between the gauge and the stem A, a rubber washer 34 is interposedbetween the disk I1 and the end of the valve stem A. `As the gauge is screwed onto the stem A, the member I8 engages and presses inwardly on the tire valve, thus causing air from the valve and the tire to which the valve is connected, to flow through theV air inlet and into an air chamber 31 which is defined by the space between the diaphragm 2| and the disk Il. As the air enters the air chamber 3l, the pressure flexes the diaphragm 2| which causes the diaphragm to move inwardly as does the stud 30. Inward movement of the stud 30 causes the pin 32 to move in the spiral groove, and

accordingly turns the shell member 28and the indicating pointer 29. The movement of the indicating member 28 is proportional to the amount of air pressure present in the air chamber 31, thus a reading of the air pressure of a tire may be determined by looking through the transparent lens 26 to view the indicating pointer 29 relative to the readings on the dialdisk 2li.A 'After the tire gauge I0 has been applied to the *tire valve, it remains thereon whereby instant reading ofthe air pressure of the tire may be obtained without the necessity jof removing a valve cap and applying a testing gauge Ato the valve. It willl of course be understood that to inflate the tire, the gauge It is unscrewed from the threaded stem A of the tire valve, and after inflation, the gauge is again screwed into position upon the valve.

While I have shown and described what I con-` sider to be the most practical embodiment ofmy invention, 'I wishA itto jbe yunderstood that such its Vtop and having a bottom` wall, said bottom wall being provided with an air inlet opening coaxial with the axis of theV cylindrical casing and an annular depression around Ythe opening forming an annular shoulder adjacent the side wall of the casing, an internally screw threaded nipple extendingoutwardly from the bottom wall and" coaxial with the air inlet opening, a disk plateof a size and shape conforming to that of .the bottom wall and resting thereon, said disk plate' having a struck out portionextendingthrough the air inlet opening and into said nipple for engagement with a valve stem, said disk plate being provided with air passages in open communication with the interior of the nipple, a pressure responsive disk diaphragm having its peripheral portion resting on the peripheral portion of said disk plate whereby the main portion of the diaphragm is spaced from the disk plate, means for holding said da phragm and disk plate seated against said annular shoulder of the lbottom wall, a dial plate fixedly mounted in said casing adjacent the top open end thereof, a rotatable indicating pointer for movement overthe top face of the dial plate, means associated with the diaphragm and rotatable indicating pointer for turning same rupon flexing i movements of the diaphragm, and a transparent glass fixedly mounted in the open end of the casing and closing the same.

2. An air pressure gauge for attachment to a tire valve comprising a cylindrical casing open at its top and having a bottom wall, said bottom wall being provided with an air inlet opening coaxial with the axis of the cylindrical casing and an annular depression 'around the opening forming anannular shoulder adjacent the side wall of the casing, an internally screw threaded nipple extending outwardly from the bottom wall and coaxial with the air inlet opening, a disk plate of a size and shape conforming to that of the bottom wall and resting thereon, said disk plate having a struck out portion extending through the air inlet opening and into said nipple for engagement with a valve stem, said disk plate being provided with air passages in open communicationI with the interior of the nipple, apressure responsive disk diaphragm having its peripheral portion resting upon the peripheral portion of said disk plate whereby the main portion of the diaphragm is spaced'from the disk plate, an annular spacer collar snugly fitting within said casing having its lower edge resting upon said diaphragm, a dial plate resting upon the top edge of said annular collar, a second annular spacer collar snugly fitting into said casing and resting upon the dial plate, a transparent glass seated on the top edge of the second mentioned collar, the'top edge of the casing being rolled inwardly over the peripheral portion of the transparent glass, a rotatable indicating pointer for movement over the top face of the dial plate, and means associated with the diaphragm and rotatable indicating pointer for turning same upon flexing movements of the diaphragm.

IVY D. VFENWICK.. 

